Re: [Tutor] (OT) Flame wars
Tim Johnson [EMAIL PROTECTED] wrote allows us to embed loops and all sorts, effectively adding new command structures to the language in a way that only Lisp and Tcl have really been good at up till now. Sorry Alan, but you are leaving out rebol. Command structures in rebol are are just functions and IMHO, easier to roll your own than lisp macros. Quite right, I forgot rebol. I played with it briefly and it is a lot of fun for network programming, but ultimately I ran out of steam with it too often so gave up. Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] (OT) Flame wars (was: Amazing power of Regular Expressions...)
Greetings, all: -Original Message- Date: Mon, 6 Nov 2006 10:32:32 + From: Michael Sparks [EMAIL PROTECTED] Subject: Re: [Tutor] Amazing power of Regular Expressions... To: tutor@python.org Message-ID: [EMAIL PROTECTED] Content-Type: text/plain; charset=iso-8859-1 On Monday 06 November 2006 01:08, Alan Gauld wrote: While using a dictionary is probably overkill, so is a rage. No, in this case it's absolutely the right choice. A simple string holding all characters and an 'in' test would probably be both easier to read and faster. I'm stunned you think this. It's precisely this sort of naivete that baffles me with regard to regales. Which kind of illustrates the point of the thread I think! :-) Actually, no, it doesn't. snip I'm serious, if you think ^[0-9A-Za-z_.-]*$ is unclear and complex, go away and relearn regales. Michael. With the final sentence above, this thread has ceased to be an intellectual discussion and become a religious argument. Until then, I was enjoying an informative discussion by knowledgeable people on a topic of considerable interest. Now I'm upset by the implications of the statement and embarrassed on behalf of the writer. When a person his so convinced of his/her rightness that they feel justified in insulting those in opposition, that person has substituted flaming for advocacy. They have also, in my opinion, seriously weakened their position on the subject. Why would someone resort to such an attack if they were, in fact, correct? I am disappointed to see such behavior on this list, and I hope it's occurrence will continue to be vanishingly small. Regards, Barry [EMAIL PROTECTED] 541-302-1107 We who cut mere stones must always be envisioning cathedrals. -Quarry worker's creed ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] (OT) Flame wars (was: Amazing power of Regular Expressions...)
Wow... I had to click this e-mail just because I saw the first posts on the mentioned thread and could see it turning for the worst.. I'm serious, if you think ^[0-9A-Za-z_.-]*$ is unclear and complex, go away and relearn regales. Michael.If this is your method to helping people, you should be the one to step back and go away. While your at it, go an take an educated look at debates.. You might learn that your tactics for trying to sway your side of the opinion are harsh and completely self killing. Any point you were trying to make just became invalid because of this childish b/s. On 11/6/06, Carroll, Barry [EMAIL PROTECTED] wrote: Greetings, all: -Original Message- Date: Mon, 6 Nov 2006 10:32:32 + From: Michael Sparks [EMAIL PROTECTED] Subject: Re: [Tutor] Amazing power of Regular Expressions... To: tutor@python.org Message-ID: [EMAIL PROTECTED] Content-Type: text/plain;charset=iso-8859-1 On Monday 06 November 2006 01:08, Alan Gauld wrote: While using a dictionary is probably overkill, so is a rage. No, in this case it's absolutely the right choice. A simple string holding all characters and an 'in' test wouldprobably be both easier to read and faster. I'm stunned you think this. It's precisely this sort of naivete that baffles me with regard to regales. Which kind of illustrates the point of the thread I think! :-) Actually, no, it doesn't.snip I'm serious, if you think ^[0-9A-Za-z_.-]*$ is unclear and complex, go away and relearn regales. Michael.With the final sentence above, this thread has ceased to be anintellectual discussion and become a religious argument.Until then, I was enjoying an informative discussion by knowledgeable people on atopic of considerable interest.Now I'm upset by the implications ofthe statement and embarrassed on behalf of the writer.When a person his so convinced of his/her rightness that they feel justified in insulting those in opposition, that person has substitutedflaming for advocacy.They have also, in my opinion, seriously weakenedtheir position on the subject.Why would someone resort to such an attack if they were, in fact, correct?I am disappointed to see such behavior on this list, and I hope it'soccurrence will continue to be vanishingly small.Regards,Barry [EMAIL PROTECTED]541-302-1107We who cut mere stones must always be envisioning cathedrals.-Quarry worker's creed___ Tutor maillist-Tutor@python.orghttp://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] (OT) Flame wars
Wow... I had to click this e-mail just because I saw the first posts on the
mentioned thread and could see it turning for the worst..
Hi everyone,
So let's try to squash this one now. There are more interesting problems
to solve. Or other flame wars to fight.
Let me see if we can do something constructive. I've been doing a
shallow, superficial study of the Ruby language at the moment. One of the
things I've been impressed about is that they've managed to make lambdas
look non-threatening to people with their syntactic sugar of code
blocks.
For example,
## Ruby #
def twice
yield
yield
twice { puts hello world }
#
This prints out hello world twice in a row: the twice() function takes
in an implicit code block, which it can later call by using their
'yield' statement. What the Ruby folks are doing is trying to make the
use of higher-order procedures look really simple. In fact, most of the
encouraged idiom style I've seen so far extensively uses this code style
pervasively (especially for iteration), and that's very admirable.
The exact functionality can be done in Python, but it does look a little
more intimidating at first:
## Python
def twice(f):
f()
f()
twice(lambda: sys.stdout.write(hello world\n))
This does the same thing, but it looks a little scarier because the
concepts needed to grasp his are superficially harder than that in the
Ruby code.
Anyway, let's derail off this regex flamewar and get us back to talking
about code and about stuff that actually matters, like learning how to use
functions well.. *wink*
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Re: [Tutor] (OT) Flame wars
Danny Yoo [EMAIL PROTECTED] wrote So let's try to squash this one now. There are more interesting problems to solve. Or other flame wars to fight. I wasn't aware we were having a war, but I'm happy to desist :-) Let me see if we can do something constructive. I've been doing a shallow, superficial study of the Ruby language at the moment. One of the things I've been impressed about is that they've managed to make lambdas look non-threatening to people with their syntactic sugar of code blocks. Ruby blocks are almost as good as Smalltalk blocks for this kind of thing and very powerful. Regular readers will know I have often expressed dissappointment at the limitations of Python's lambdas, it's one thing the Ruby boys have got right IMHO. The exact functionality can be done in Python, but it does look a little more intimidating at first: ## Python def twice(f): f() f() twice(lambda: sys.stdout.write(hello world\n)) This does the same thing, but it looks a little scarier because the concepts needed to grasp his are superficially harder than that in the Ruby code. The other advantage in Ruby is that the block can be arbitrarily complex, not just a single expression as in a Python lambda. This allows us to embed loops and all sorts, effectively adding new command structures to the language in a way that only Lisp and Tcl have really been good at up till now. Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] (OT) Flame wars
Chris Hengge wrote: I may have just missed the point to your attempt to derail this conversation =P Ah, well, don't worry. I didn't learn of lambda until I'd been using Python for a year or more. I was trying to pass arguments to callbacks in TKinter. one of the Pythonistas (Alan, Danny, Kent) told me Oh, that's trivial with lambda and since then, I've tried to read up on lambda and Functional Programming in general. However.. Why do all that when you can just str = Hello World print str * 2 (Maybe I missed some concept that this small example doesn't accuratly reflect) Yes, I do believe you're correct here, Chris :) I will not presume to know enough about lambda to explain it to you, but I will refer you to these articles: http://www.secnetix.de/~olli/Python/lambda_functions.hawk and Alan Gauld's tutorial, of course :) specifically, the page http://www.freenetpages.co.uk/hp/alan.gauld/tutfctnl.htm Or browse there from the main page http://www.freenetpages.co.uk/hp/alan.gauld/ click 'functional programming' under Advanced Topics' if you want the menu frame to remain on the left of the screen. Consider this: You don't say outputstring = Hello, World! print outputstring because you're only using the string once, and it's not something that would look ugly all on one line. Instead, you do print Hello, World! An alternate example: a_list = [[a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a], [a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a], [a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a], [a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a]] print a_list would make more sense than print [[a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a], [a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a], [a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a], [a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a,b,a]] because then if you need to change the list, or use it again somewhere, you don't have to go through the pain of typing it out each time, since in the first case, you assigned it to a variable, a_list. The long and short of it is: (or more specifically, the short of it) lambda lets you define functions you don't have to bind to a name. so, supposing you have the function def call_a_function(a_function): a_function() That will call a function object, you can do something like this: def f(): sys.stdout.write(Hello, World!) call_a_function(f) or you could do call_a_function(lambda: sys.stdout.write(Hello, World!)) It's like the string example above. It's a waste to have the function definition on two lines, and the call on another line, if the function's compact enough to fit on a single line using lambda. But also note that you can't reuse the lambda function unless you store it in a variable. In this way, it's similar to the 'print Hello, World!' statement. I hope that helps you, Chris. -Luke ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] (OT) Flame wars
* Alan Gauld [EMAIL PROTECTED] [061106 14:01]: The other advantage in Ruby is that the block can be arbitrarily complex, not just a single expression as in a Python lambda. This allows us to embed loops and all sorts, effectively adding new command structures to the language in a way that only Lisp and Tcl have really been good at up till now. Sorry Alan, but you are leaving out rebol. Command structures in rebol are are just functions and IMHO, easier to roll your own than lisp macros. But with freedom comes responsibility. (Tim: rebol = 50% python = 50%) -- Tim Johnson [EMAIL PROTECTED] http://www.alaska-internet-solutions.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] (OT) Flame wars
On Mon, 6 Nov 2006, Chris Hengge wrote:
I may have just missed the point to your attempt to derail this
conversation =P
Hi Chris,
Ah! Are we talking about regular expressions anymore?
No?
Good. *grin*
Why do all that when you can just
str = Hello World
print str * 2
Let me do a more substantial example. As you know, Python's for loop
works on iterables:
#
for x in list(hello):
...print x
...
h
e
l
l
o
#
We're running a for loop across a list of characters. In this case, our
list is iterable. (We could iterate directly on the string itself, but
let's stick with lists for the moment.) An iterable in Python is
something that can give us an iterator.
###
my_iterator = iter(list(hello))
###
An iterator is something that responses to next() requests until we
consume everything:
#
my_iterator.next()
'h'
my_iterator.next()
'e'
my_iterator.next()
'l'
my_iterator.next()
'l'
my_iterator.next()
'o'
my_iterator.next()
Traceback (most recent call last):
File stdin, line 1, in ?
StopIteration
##
So there's a few layers of indirection here.
iterable - iterator - elements
Ruby takes a different approach: they also have an iterator protocol, but
what they require is something that provides an each() method. For
example:
irb(main):002:0 'hello'.split(//).each {|c| puts c}
h
e
l
l
o
This each method takes in a code block, and runs it on every element in
the thing we're iterating across. The iterable itself provides the
looping mechanism instead of the client code.
The concept sorta looks like this in Python:
###
class MyString:
def __init__(self, s):
self.s = s
def each(self, f):
i = 0
while i len(self.s):
f(self.s[i])
i = i + 1
MyString(hello).each(lambda c: sys.stdout.write(c + '\n'))
This, too, iterates across our iterable.
The one handling the control flow is the 'each' method, which is a little
wacky to think about at first. The Ruby folks make this work because
their syntax is custom tailored for this pattern, so it's easier to read
and write.
I'm probably not doing it much justice with my ugly examples. *grin*
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Re: [Tutor] (OT) Flame wars
On Monday 06 November 2006 22:52, Alan Gauld wrote: I wasn't aware we were having a war, but I'm happy to desist :-) FWIW, I wasn't aware of one either. (Mind you I've often noticed what passes for plain speaking in the UK passes for vehement flame war elsewhere, so maybe that's it) Anyway, if that's what people here think a flame war looks like... Well, a) I'll try and avoid such /mild/ comments in future ;) b) good for such people, real flame wars are really nasty ! Michael. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
